Narcissism can be manifested in different ways, and sometimes it's not obviously apparent that a politician is a malignant narcissist. With David Cameron, the signs had been there for years; likewise, with Turkey's leader, Recep Tayyip Erdogan, it has been clear what type of persona has been running the country. Cameron liked to call himself the "heir to Blair", and he certainly possessed the same kind of superficiality and short attention span as the former Labour leader. Blair's successor, Gordon Brown, exhibited narcissism in a different manner (insiders talked of paranoia, control-freakery and furious bouts of anger), which made him and Blair's character's as chalk and cheese. The child of a priest, Brown's personality was more serious and workmanlike, whose narcissistic traits (brazenly calculating and authoritarian) would reveal themselves when under pressure. Cameron's successor, Theresa May, another priest's offspring, seems to be in the same (narcissistic and insecure) mould as Brown.
As they say, history doesn't repeat itself, but it often rhymes.

A cynical opportunist

Theresa May's rise to power was accidental, but also nakedly opportunistic. The irony is that in her early years as a politician, she was the one who invented the "Nasty Party" label, setting herself out as a moderate and visionary against the reactionary tendency that dominated the Tory Party before Cameron became leader in 2005. This put her in good stead when Cameron took over and changed the agenda of the party to a more liberal one.
By the time the Conservatives won power in 2010, in the name of "reform" and "austerity" the "Nasty Party" label became not something to be avoided, but for some almost appeared a badge of honour. Ministers out-did each other in where they could reduce the size of the state and cause the most upheaval in the civil service and public sector. Theresa May, in her role as Home Secretary, was at the forefront of this in her drive to reduce the size of the police, regardless of insiders telling her of the potential effects on crime and the threat of terror. At the same time, the abject failure of the government's target to reduce immigration to the "tens of thousands" (when it in fact surged to ever higher heights) was something that Theresa May was keen to obfuscate on and ignore as an inconvenient truth. Whenever challenged over the numerous scandals that hit her department over the years, May was brazen in her efforts to intimidate and blame others; all of this was noted gratefully by Cameron as a sign of her political usefulness.
Her role as Home Secretary, supposedly overseeing immigration, should have put her in the spotlight when the EU referendum campaign started, but, as was typical of her, she went "submarine" during this crucial phase, leaving her contribution to the debate to a rhetorically-minimal speech that covered her bases with the government's (pro-EU) standpoint, but with a vagueness that left open her real allegiances.
So this left her in a key position as an apparent "safe pair of hands" when the EU vote was lost and Cameron resigned. And it was at this moment that May decided to "own" Brexit: in a piece of naked political opportunism, she took the Conservatives into UKIP territory.

As Home Secretary, it was known among associates that she brooked no opposition, and kept a tightly-knit circle of loyalists. Two of these have since continued with her into Number Ten as her joint chiefs of staff (who also helped with the current manifesto - more on that later).
This paranoid "bunker mentality" (most recently associated with Gordon Brown) continued with her into Downing Street: almost her first act as Prime Minister was to get rid of those seen as a threat (and often the most competent in cabinet): George Osborne's sacking seemed gratuitously sadistic in the bluntness of its execution, while others such as Nicky Morgan (whose loyalty was deemed suspect), and Michael Gove (who was never forgiven for a tempestuous row over the "Trojan Horse" scandal in the previous parliament) seemed a personal vendetta. Of those left and those brought in to replace the casualties, the foreign policy "triumvirate" of Boris Johnson, David Davis and Liam Fox might as well be called the "three stooges": each of them lending themselves to caricature for their frequent buffoonery and/or questionable competence.
Of those in office, Hammond seems the most quietly competent (though even his days may be numbered); the rest are there more for their incidental usefulness to May (e.g. as political protection) or their unquestioning loyalty (due to patronage or ideological overlap). Apart from Hammond, none of them have any obvious competence beyond the ability to talk nonsense to the media when required. It has only been the amateurish state of the opposition that has saved their blushes so far (and thus created an aura of complacency around Theresa May and her "team"). In this way, May's cabinet is a manifestation of her own narcissism; surrounding herself with loyalists and incompetents that will do as they're told.

Whose idea was the "personality cult" thing? Given May's evident social awkwardness (who makes Gordon Brown seem like a rhetorical giant on the stump compared to herself), was it all due to her over-confidence and narcissistic complacency? While less superficial than Cameron, May's narcissism seems more "cerebral" than "somatic": she complacently thinks she is smarter and more charismatic than she actually is, and thus comes across as arrogant and robotic instead. Deep down, she obviously knows all this, which must feed the innate insecurity that all narcissists have, making her react even more unnaturally. Her initial popularity was probably down to a combination of factors after the Brexit vote, rather than due to anything in particular that made her stand out. It was this popularity - which now seems to have dwindled under the stark spotlight of actual attention - that must have led to the initial "personality cult" strategy.

A contemptuous autocrat

The fact that she had repeatedly said (through her minions) that there was no reason for an early election, and then to suddenly call one out of the blue (even to the surprise of ministers), displays a callous contempt for the intelligence of the electorate, the media, and her peers. The fact that she positioned herself as "different" from the "games" played by Cameron and Osborne, only for her to carry out the most cynical of "games" to call an election three years early, demonstrates what little regard she has for political niceties. Brown was lampooned as a "bottler" by the Tories for not calling an early election shortly after becoming PM; May has torn all precedents up by having one, not only so soon after the last one, but after many months of repeatedly saying she wouldn't have one, and then pretending that its timing wasn't for naked political gain, but instead blamed the opposition (for daring to oppose!). Again, this treats the electorate with contempt. While this is hardly the first time an early election has been called, never before has it been done under such disingenuous circumstances.
This contempt for the electorate was added to with her decision not to have a proper debate with the other party leaders. While Cameron was rightly criticised during the 2015 election for brazenly manipulating the terms of the debate for his own ends, at least he decided to have one. Theresa May can't even be bothered to do that; instead her terror at being found out to be a terrible speaker under pressure means that she attacks the other parties from the sidelines like a coward and a bully. This alone ought to disqualify her from being PM; she doesn't even have the strength to defend her own record before her peers and under public scrutiny. Because Cameron did his best to avoid proper scrutiny before, she thinks she can go one better and avoid it completely, or send someone else in her place.
These are strange times, and they became even more bizarre when, only a few days after launching the Conservative manifesto. one of its key proposals was dropped. For a party to change its manifesto during an election campaign is unprecedented in modern political history, and the fact that May tried to paper over this as though nothing had happened, shows again how detached she is from reality: only a delusional narcissist could think that she could get away with pretending that no-one would notice or realise that this was a massive deal. May's U-turn came about due to a poorly-planned manifesto that took the electorate for granted; another sign that "Theresa May's team" thought that they could offer up any old nonsense and people would vote for it, showing their contempt for the opposition as well as the electorate.
As time has gone on, we have also seen how personal attacks against her opponents, and Jeremy Corbyn in particular, have been used again and again, especially during the election campaign. These attacks usually bear no relation to reality. Somehow, Corbyn is "dangerous" to the country, while she offers "strong and stable" leadership. Both these assertions are evidently laughable: compared to the economic chaos that the coming years of Tory-led Brexit offer, Corbyn's agenda is hardly terrifying - only "terrifying" to the Tories' ultra-rich, tax-dodging, donors; and May's leadership credentials have just been shot to pieces by her manifesto U-turn. One of the major differences in character between May and Corbyn is that Corbyn clearly enjoys campaigning and enjoys being with people (something that - shockingly - he and Cameron have in common!); by comparison, May seems twitchy and nervous, and completely robotic.

Theresa May's arrogance, complacency, as well as her innate insecurity and resulting autocratic behaviour are all clearly evident. Her public events are strictly limited to party functionaries, so that she is surrounded by sycophants that won't challenge her. Her media appearances are controlled so that she receives only limited air-time. The "Supreme Leader" is only all-powerful because she is unchallenged; her veneer of respectability and competence is supported, like the "Wizard Of Oz", by a complex facade; once the mask slips off, the real pygmy behind it is revealed.